Apparatus for vacuum treatment of molten metal



A. SICKBERT 3,193,892

APPARATUS FOR VACUUM TREATIENT OF HOLTEN IETAL July 13, 1965 Filed March 19, 1963 II II 10 9 26 Jnvenfar:

ADOLF SICKBERT BY 1 'QMPM & ,6

' ATTORNEYS.

United States Patent 3,193,892 APPARATUS FOR VACUUM TREATMENT OF MGLTEN METAL Adolf Siclrbert, 'WattenscheidEppendorf, Germany,

assignor to Bochumer Vcrein fiir Guhstahlfabrilration Aktiengesellschaft, Bochum, Germany, a German corporation Filed Mar. 19, 1963, Ser. No. 266,377 Claims priority, application Germany, Mar. 22, 1962, B 66,466 1 Claim. (Cl. 2285) The vacuum treatment of metal, especially steel, can be performed by tapping the metal from the furnace, or other vessel into a ladle wherein the metal is subjected to a vacuum suitable for the desired treatment, such as degassing. Following such treatment, the molten metal is discharged from the ladle. The vacuum vessels or ladies used for the vacuum treatment are commonly provided with a discharge spout disposed in the bottom thereof, and for use in the discharging of the molten metal from the ladle: The discharge spout is outfitted with an openable stopper. A problem exists with respect to providing a suitable seal at the discharge spout. The vacuums commonly used in the molten metal vacuum treatment are 0-0.1 mm. mercury in the degassing of steel, for example, and the vacuums are preferably in the range of about 15-0.1 mm. mercury.

It has been proposed to provide an enclosure for the spout or valve to shield it from atmospheric pressure and thereby provide a suitable seal for the spout. Such enclosures may comprise a membrane seal having a bayonet closure under the spout or fixedly mounted in such a manner that it is melted upon discharge of the molten metal. Sliding valve seals are also known.

The principal object of the invention is to provide an improved seal for the discharge spout. According to the invention, provision is made for evacuating the space within the spout enclosure before or during the time of the evacuation of the ladle. The desired vacuum can be provided by communicating the enclosure with a vacuum line, vacuum pump, or with the inside of the ladle in the upper part thereof so that the enclosure is communicated with the vacuum to which the ladle is exposed.

The invention provides advantages in respect to safety, both in regard to the equipment and in regard to personnel. Thus, in the case of the apparatus of the prior art, explosions can occur due to the accumulation of water. The spout, desirably, is of refractory material and is likely to hold water so that upon the rapid heating, such as occurs during the vacuum treatment, explosion is likely. Furthermore, moisture is apt to accumulate in the vessel when the vessel is initially exposed to vacuum before molten metal is introduced therein. The invention provides a safeguard against accidents as may be occasioned by the conditions described.

The invention is further described in reference to the accompanying drawings, wherein:

FIG. 1 is an elevation view, in cross-section, showing schematically apparatus according to the invention;

FIG. 2 is an enlarged view of a portion of apparatus according to the invention, and indicating a modified construction; and

FIG. 3 is an elevation view, in cross-section, showing schematically another embodiment of apparatus according to the invention.

The apparatus of the invention comprises: (a) a ladle for the molten metal during the treatment; (b) a dis- 3,l3,8$2 Patented July 13, 1965 charge spout for discharging treated molten metal from the vessel having a passageway extending therethrough for passage of molten metal, and an inlet end disposed for receiving molten metal from the vessel and an outlet end disposed for discharging the molten metal, said spout extending through a wall of the ladle; (c) a stopper for opening and closing the spout passageway; (d) a sealing enclosure for said spout outside the vessel; and (e) means for communicating said sealing enclosure with a vacuum. The apparatus can further include means for communicating molten metal within the ladle witha vacuum, and, advantageously, the sealing enclosure vacuum means and the ladle vacuum means are in communication, so that one vacuum source, such as a vacuum pump, can be utilized to provide both of the vacuums.

Referring to the drawings, in the embodiment shown in FIG. 1, the apparatus includes a ladle 1 outfitted with a vacuum-tight closure 2. The closure 2 has an inlet opening 3, and mounted atop the closure 2 is a funnel 5 which can contain molten metal. The funnel 5 is provided with the bottom seal 6 which provides a vacuumtight mounting of the funnel 5 on the closure 2, and the funnel 5 is provided with an outlet 4. The outlet 4 is vacuum tight sealed by a sealing member, a membrane 9'. Disposed immediately below the outlet 4 in the cover 2, is the opening 3, so that molten metal passing through the outlet 4 of the funnel 5 passes to within the ladle 1. The closure 2 is provided with an opening 23 for communicating the inside of the ladle with a vacuum source.

The ladle 1 is provided with a discharge spout 24 in cluding the seat 7 and the stopper 8. The seat 7 can be of refractory material and the stopper 8 can likewise be of such material. Suitable means (not shown) are provided for selectively opening and closing the spout 24 by operation of the stopper 8 to shift it between the closed condition shown in FIG. 1, and the open condition wherein it is raised from the valve seat 7. An enclosure is provided for the discharge .spout on the outside of the ladle. The enclosure includes the ring 25 which can be permanently secured to the ladle 1, and the cover plate 9. The cover plate 9 can be secured to the ring 25 by any suitable means such as bolting 26. In a preferred construction of the discharge spout 24, the valve seat 7 is received in an annular steel ring 14 and the ring 14 is secured in place in the bottom of the ladle 1 by a weld which joins the outer portions of the ring 14 with steel of the ladle. On the inside of the ladle, the ring 14 can be flush against the refractory lining (not shown) of the ladle 1. The cover plate 9 can be of any suitable material. If desired, it can be a material which is meltable so that the seal provided by the enclosure is opened by allowing molten metal to flow through the spout 24 and melt the cover plate. To communicate the space 19 within the spout enclosure with vacuum, conduit 11 is provided. The conduit 11 is connected adjacent the enclosure with a rubber coupling 16, and, its other end communicates with the vacuum pump conduit 23. Thus, vacuum to which the inside of the ladle is exposed will also work on the space 10 within the enclosure. This will provide a pressure equalization across the spout 24, so that leakage will not occur.

The embodiment shown in FIG. 2 depicts a modified construction. In this embodiment, the seat 7 is received directly by the wall of the ladle 1, and the conduit 11 extends through the annular ring 26.

In the embodiment shown in FIG. 3, the ladle 1, instead of being outfitted with a vacuum-tight closure as is the case for the embodiment shown in FIG. 1, is positioned Within a vacuum chamber 13. The vacuum chamber l? has a vacuum-tight closure 21 provided with an 7 opening 23 for communicating the inside of the vacuum the discharge spout 24 is provided by the means drawing a vacuumon the ladle 1. Thus, this' vacuum is communicated with the space 10 through the opening 22, provided the ladle 1 is not vacuum tight sealedat its bottom. When the bottom of the ladle lis tightly sealed arrangedfa conduit like conduit'll in FIG. 1; must be 'used.

' In the operation of the apparatus of the invention, the

vacuum can be impressed upon the. molten metal duringthe timethat the metal is flowingfrom the funnel 5 into thevacuum maintained on the ladle 1. The invention particularly contemplates such operation as greatest advantage of an enclosurefor the dischargespout provided with vacuum, is realized in the course of such operation. A1ternativ'ely,'however, the apparatus can be operated in the manner that the molten metal is first placed in the ladle 1 and thereafter a vacuum is drawn on the ladle.

While the invention has been described with respect to particular embodiments thereof, these embodiments are merely illustrative of the invention and do not define the limits thereof.

What is claimed is:

'Apparatus for the vacuum treatment of molten metal comprising:

(a) a ladle for holding the molten metal during the treatment;

(b) a discharge spout for discharging treated metal from the vessel having a passageway extending therethrough for passage of'molten metal and an inlet end disposed for receiving molten metal from the vessel and an outlet end disposed for discharging the molten metal, said spout extending through a wall of the ladle; l

(c) a stopper for opening and closing the spout passageway; f a 1 Y (d) "a closure cap enclosure for-said spout outside the vessel and injsealed relation with the wall of the vessel adjacent the discharge spout, said closure being openable;

-(e) conduit'means communicating said closure with the inside of saidladle at the upper part thereof.

References Citedib y the Examiner UNITEDSTATES PATENTS 2,117,114 5/38 Hale 1 -22 73 DAVIDL. RECK, Primary Examiner. 

